Two cases of unilateral cone-rod dysfunction with negative electroretinograms

HIGH MYOPIA IS COMMON IN PATIENTS WITH X-LINKED RETINOPATHIES: Myopic Maculopathy Analysis

PURPOSE

High myopia can occur as a single or syndromic condition. The aim of this study was to evaluate the refractive error and myopic maculopathy in patients with X-linked retinopathies.

METHODS

Whole exome sequencing, Sanger sequencing, and comprehensive ocular examinations were performed in patients with X-linked retinopathies.

RESULTS

A total of 17 patients were recruited, including six with CACNA1F, seven with RPGR, three with NYX, and one with OPN1MW mutations. The diagnoses were congenital stationary night blindness (6), cone-rod dystrophy (4), retinitis pigmentosa (4), achromatopsia (1), Leber congenital amaurosis (1), and myopia (1). Myopia was present in 88.2% patients, and 64.7% patients had high myopia. Gene analysis showed that high myopia was present in 80% patients with CACNA1F, 100% patients with NYX, and 57.1% patients with RPGR mutations. In the ATN classification, 64.7% of the patients were A1T0N0 and 35.3% were A0T0N0. The refractive errors progressed over time, even in patients with congenital stationary night blindness. Two females with heterozygous de novo RPGR mutations presented with retinitis pigmentosa or cone rod dystrophy combined with high myopia.

CONCLUSION

High myopia is common in patients with X-linked retinopathies, and myopic maculopathy was only mild atrophy without traction and neovascularization.

Acute unilateral inner retinal dysfunction with photophobia: importance of electrodiagnosis

PURPOSE

To establish with negative electroretinogram (ERG) the clinical entity of eight patients with unilateral severe photophobia, essentially normal fundus, good visual acuity, and severe cone and rod dysfunction.

STUDY DESIGN

Multicenter retrospective observation case series.

METHODS

Comprehensive ophthalmologic examinations were performed, including best-corrected visual acuity (BCVA), full-field ERGs and multifocal ERGs (mfERGs), fundus photographs, and OCT. Systemic and genetic examinations were performed.

RESULTS

The mean (± SD) age at the onset was 60.0 ± 8.4 years, and the six patients noticed severe photophobia in the affected eye in spite of almost normal fundus appearance and good BCVA. The dark-adapted bright flash ERGs in the affected eye had relatively well-preserved a-waves and depressed b-waves, i.e., a negative ERG. Cone ERGs and both b- and d-waves of the photopic long-duration ERGs were almost undetectable. Rod ERGs were severely reduced; however, only two patients complained of night blindness. In five patients, the mfERGs were extinguished in the periphery but preserved in the central retina, resulting in good BCVA. Electrophysiological findings indicated a severe diffuse dysfunction of the inner retina affecting bipolar cells of both ON- and OFF-pathways, and in five patients there was a reduction in the thickness of the inner nuclear layer. In seven patients the retinal arteries were attenuated. Anti-retinal antibodies were detected in the serum of two patients. No genetic causes were found.

CONCLUSIONS

The common features in the eight patients with unilateral negative ERGs suggest a new disease entity of unilateral acute inner retinal layer dysfunction. In most patients, the only subjective complain was photophobia.

Unilaterally extinguished electroretinograms in an eye with normal visual acuity and visual field

PURPOSE

This study reports a case of unilateral retinopathy with extinguished full-field ERGs (ffERGs), wherein the visual acuity was 16/16 and the visual field was spared.

METHODS

Observational case report.

RESULTS

A 39-year-old female had developed nyctalopia in her left eye. Two years later, she visited an ophthalmologist who noted a bilaterally reduced pigmentation of the fundus. Her best-corrected visual acuity was 16/16 in both the eyes. Goldmann perimetry demonstrated that her visual field was bilaterally fully spared. ffERGs measurement was performed in accordance with the ISCEV standard protocol and indicated that her right eye was normal. However, all ERG responses were severely attenuated in her left eye. Multifocal ERG responses were found to be normal in the right eye and extinguished in the left eye except for residual responses that were exclusively located at the center. During the 7 years of the follow-up period, the visual field in the left eye, which was once normal, became shaded, and the development of a ring scotoma was identified. The visual field in the right eye is still full.

CONCLUSIONS

The pathogenesis of this patient's condition still remains unknown, while unilateral retinitis pigmentosa, unilateral pigmentary retinopathy, acute zonal occult outer retinopathy, and autoimmune retinopathy can all be considered as possible explanations. The uniqueness of this case study is that the extinguished ERG responses are predictive of the functional alteration in the affected eye, when the initial visual acuity and the visual field were normal.